They compiled a data base of 1046 musicians - solo artists and band members - who had a No. 1 album in the British charts between 1956 and 2007, a net that included balladeers, pop singers, R&B and heavy metal.

The first No. 1 was Frank Sinatra's Songs for Swinging Lovers! on 28 July 1956, and the last was Leona Lewis' Spirit on 18 November 2007.

During the period under study, 71 of the musicians died, equivalent to seven per cent of the sample.

But there was no peak at all in deaths at the age of 27.

On the other hand, musicians in their 20s and 30s were two to three times likelier to die prematurely than the general British population.

"The 27 Club is unlikely to be a real phenomenon," according to the paper, which appears in the British Medical Journal

"Fame may increase the risk of death among musicians, but this risk is not limited to age 27."

Historically, the big risk period for rock'n'roll fame appears to be the 1970s and early 80s, the researchers say.

After that, the number of deaths among the chart-toppers fell sharply. Indeed, there was a period in the late eighties when there were no mortalities at all.

Why this is so is unclear - it could be that treatment for drug overdoses and addiction improved, and thus saved musicians in danger.

Does success fuel risky behaviour?

The 27 Club gained currency with Winehouse's death in July, prompting the explanation that musicians often become famous in their early twenties, and their risk-taking peaks four to five years later.

A more insidious argument was that musicians craving immortality subconsciously became bigger risk-takers, or even committed suicide, in order to join rock's dead elite.

Faithful to the principles of scientific rigour, the authors of the study acknowledge that the data trawl has some flaws.

Three of the '27 Club' - Jimi Hendrix, Janis Joplin and Jim Morrison - did not have a No. 1 album in Britain and were thus excluded.

Kermit the Frog also had a No. 1 at this time with the Muppets.

The bulgy-eyed amphibian and his chums are not known for substance abuse or playing with guns.

So in an act of statistical fairness, the study included the mortality rate among the actors who played their parts.